This is a prospective, randomized, multicenter, controlled trial. One hundred sixteen patients with primary membranous nephropathy (PMN) will be randomly divided into the intervention and control groups. The intervention group will be administered maximum tolerable dose of ACEI/ARB and finerenone 20 mg QD. Control patients will be administered maximum tolerable dose of ACEI/ARB. The primary endpoint is the relative change in urinary protein content from baseline to 6 months.

After more than 4 weeks of maximum tolerated dose of ACEI/ARB, the patients will be randomly divided into the control and intervention groups in a 1:1 ratio. The intervention group will then be administered finerenone 20 mg QD, while control cases will continue on their ACEI/ARB therapy.

Inclusion Criteria:

• Adults (age≥18,and ≤75) with primary MN.
• Administration of the maximum tolerable dose of ACEI/ARB for ≥4 weeks.
• BP ≤140/90 mmHg.
• Urine protein content of 1.0-5.0 g/d.
• eGFR ≥60 (CKD-EPI).
• Postmenopausal or postoperatively infertile status or on medical contraception (considering the potential risk of thromboembolism in patients with kidney disease) in women.
• Voluntary signing of informed consent.

Exclusion Criteria:

• Type 1 or type 2 diabetes. Patients with a recent history of steroid-induced diabetes were eligible with renal biopsy showing no evidence of secondary diabetic nephropathy within 6 months before the screening period.

• Patients with secondary membranous nephropathy (e.g., due to hepatitis B and C, systemic lupus erythematosus, drug therapy, malignant tumors and other secondary causes).

• Uncontrolled arterial hypertension.

• Treatment with glucocorticoids, immunosuppressants and/or biological agents in the past 6 months.

• Treatment with any other study drug within the last month.

• Females with a positive pregnancy screening test, lactating or planning to become pregnant in the next 24 months. Female or male patients unwilling to use contraceptive methods throughout the study.

• A history of mental illness.

• Laboratory tests meeting the following criteria:

  1. Hemoglobin levels <80 g/L;
  2. Platelet count <80×109/L;
  3. Neutrophil count <1.0×109/L;
  4. Aspartate aminotransferase (AST) or amino aminotransferase (ALT) >2.5 times the upper limit of normal, except in relation to the primary disease.

• Very high-risk cases (life-threatening nephrotic syndrome or unexplained rapid deterioration of renal function).

• Unsuitability for inclusion in the trial as judged by the investigator.